Question

Sophie can peel all the potatoes by herself in 45 minutes, while it would take Simon 30 minutes to do the job working alone. If Sophie and Simon work together to peel the potatoes, how long will it take them?

Answer 1

18 minutes

Explanation:

Sophie can peel all potatoes in 45 minutes, in 1 minute she can peel:

• 1/45 of all the potatoes

Simon can peel all potatoes in 30 minutes, in 1 minute he can peel:

• 1/30 of all the potatoes

Together, in 1 minute they can peel:

• 1/45+1/30= 2/90+3/90= 5/90= 1/18 of all the potatoes

To peel all the potatoes they need:

• 1 ÷ 1/18= 1 × 18= 18 minutes

So it will take them 18 minutes to peel all the potatoes